Color forming agents for the peroxide color intensifying process

ABSTRACT

PROCESS FOR THE PRODUCTION OF PHOTOGRAPHIC DYE IMAGES BY IMAGEWISE DECOMPOSITION OF PEROXIDE COMPOUNDS IN THE PRESENCE OF REACTANTS FOR A COLOR FORMING OXIDATION COUPLING REACTION WHEREIN THE REACTANTS ARE ORGANIC COMPOUNDS WHICH CONTAIN A CN SINGLE OR DOUBLE BOUND AND IN WHICH THE CARBON ATOM IS SUBSTITUTED WITH A HYDROXY-OR AMINO-SUBSTITUTED ARYL GROUP AND THE NITROGEN ATOM IS SUBSTITUTED WITH A HYDROXY-OR AMINO-SUBSTITUTED ARYL GROUP OR IS A RING MEMBER OF A HETEROCYCLIC SATURATED OR UNSATURATED 5-OR 6-MENBERED RING.

United States Patent date 3,817,751 COLOR FORMING AGENTS FOR THEPEROXIDE COLOR INTENSIFYING PROCESS Reinhart Mateiec and Walter Puschel,Leverkusen, Germany, assignors to Agfa-Gevaert Aktiengesellschaft,Leverknsen, Germany No Drawing. Filed Apr. 21, 1972, Ser. No. 246,387Claims priority, application Germany, Apr. 24, 1971,

P 21 20 091.9 Int. Cl. G03c 1/00 US. Cl. 96-48 R 2 Claims ABSTRACT OFTHE DISCLOSURE Process for the production of photographic dye images byimagewise decomposition of peroxide compounds in the presence ofreactants for a color forming oxidation coupling reactiion wherein thereactants are organic compounds which contain a CN single or double bondand in which the carbon atom is substituted with a hydroxyoramino-substituted aryl group and the nitrogen atom is substituted with ahydroxyor amino-substituted aryl group or is a ring member of aheterocyclic saturated or unsaturated 5- or 6-membered ring.

The invention relates to a process for the production of photographicimages by imagewise decomposition of peroxide compounds in the presenceof compounds for a color forming oxidation reaction.

The production of photographic images by imagewise production ofcompounds which catalyse the decomposition of peroxide compoundsfollowed by imagewise formation of dyes by oxidative coupling is knownper se. By catalytic decomposition is meant here the catalyticactivation of the peroxide which is required for the color formingoxidation reaction.

In this process a light-sensitive layer is exposed imagewise to producein imagewise distribution nuclei of noble metals of Groups Ib and/orVIII of The Periodic Table. The layer containing the nuclei is thentreated with peroxide compounds which decompose cataltyically at thenuclei in the image areas in the presence of reactants for a colorforming oxidation reaction.

Instead of using light-sensitive layers which on exposure form metalnuclei which will decompose peroxide compounds, the layers used for theabove mentioned process for the production of photographic images maycontain substances which yield other peroxidase active catalyst onexposure. Suitable for this process are, for example, certain complexcompounds of heavy metals of Groups VIb, VIIb and VIH of The PeriodicTable with a monobasic or polybasic carboxylic acid or other ligands.Compounds which split off iodine ions on exposure to light I have thesame effect.

The process may also be carried out with light-sensitive photographicmaterials which contain, uniformly distributed, catalase active enzymessuch as catalase, peroxidase, haemoglobin or haemin which areinactivated in the image areas when exposed to actinic light. Directpositive images are obtained with these materials.

It is among the objects of the present invention to improve the abovedescribed process for the production of photographic dye images by meansof new reactants for the oxidative coupling reaction, in order toincrease in velocity of dye formation, the color density and thestability of the dye image.

We now have found a process for the production of photographic imagesincluding the steps of imagewise ex- Patented June 18, 1974 posing alight-sensitive layer to form nuclei which decompose peroxide compoundsfollowed by treatment with catalytically decomposable peroxide compoundsin the presence of reactants for a color forming oxidative couplingreaction wherein the color forming reactants are organic compounds whichcontain a CN single or double bond and in which the carbon atom issubstituted with a hydroxy-substituted or amino-substituted aryl groupand the nitrogen atom is substituted with a hydroxy-substituted oramino-substituted aryl group or is a ring member of a heterocyclicsaturated or unsaturated 5- or 6-membered r-mg.

Reactants of the following general formulae have proved to be especiallysuitable:

R: Rih Ric-1i i l I I wherein R -=aryl substituted with hydroxyl and/oramino groups, especially phenyl, which aryl groups may also containadditional substituents, e.g. alkoxy having up to 18 preferably up to 5carbon atoms, halogen such as chlorine, bromine or iodine, alkyl groupshaving up to 18 and preferably up to 3 carbon atoms, sulfo, esterifiedsulfo, carboxyl or esteri-fied carboxyl or nitrile;

R =hydrogen, alkyl having up to 18, preferably up to 5 carbon atomswhich may contain additional substituents, e.g. carboxyl or hydroxyl oraryl, in particular phenyl in which the phenyl ring may contain thesubstituents listed under R R and K, have the same meaning as R R hasthe same meaning as R or alternatively R and R and/or R and R may alsodenote the ring members required to complete a heterocyclic saturated orunsaturated S-membered or 6-membered ring which contains nitrogen.

The nitrogen atom of the CN-bond in the above formulae may be present inquaternized form.

Particular utility is exhibited by the following compounds:

1 HO CH=N NH Mag? a. cm

ACE.

n on-Q01; cm

' OCH: 5

(ll-@CHNHO H NH: (all Br CHZNH NH: 0H 19 9 (|)H CHzNH NH: OH 20 CHzNHNH: OH 21 11 OH (3H CHzNH NH: H

CHzNH OH: 5 NH! OHJZ 23 CHzNH OH CHzNH OH @OHMHO NH: N H2 0H @CHMHO NH:CHa-flT-CH:

0H @CIHNHU l I N H: Czfla-N-CzH;

o H @4: Hump-O I NH: N HI CHzNH CH;

( n: 34 011 e CHQIII CH2N\/\/S 01 NH, 011 NH:

()H 1 CH2NH NHCH CHzN 0H Q NH, NH:

15 35 OH NH: OH I CIJH oH2 CH2I| OH I NH: H

NH: 0H 37 OH The above compounds are prepared by known processes. Thepreparation of some of these compounds is described in detail below; theothers are obtained by analogous methods.

Compound 1 7.3 g. of vanillin and 5.6 'g. of4,4'-diamino-diphenylaminosulfonic acid-(2) in 50 ml. of pyridine withthe addition of 5 ml. of triethylamine are heated on a steam bath forone hour. Pyridine is distilled off under vacuum and the residue isredissolved in 25 ml. of pyridine whilst hot. After cooling,

100 ml. of isopropanol are added and the reaction mixture is filteredover active charcoal.

50 ml. of glacial acetic acid and 100 ml. of isopropanol are added tothe filtrate. After one hour, the filtrate is suction-filtered andimmediately stirred up with water.

Compound 4 g. of vanillin and 8.1 g. of 4,4'-diaminodiphenylamine in 100ml. of pyridine are heated on a steam bath for 30 minutes with stirring.The reaction mixture is filtered whilst hot and the pyridine isdistilled off under vacuum. The residue is triturated with ethyl acetateand again suction filtered.

Yield: 12.5 -g.; M.P.: l94-196 C.

The preparation of compounds 6-43 has been described in British PatentSpecification No. 1,210,417.

The compounds disclosed in US. Patent Specification No. 3,535,114 arealso suitable; compound 45 is an example thereof.

Some of the above compounds are already known as photographic developingagents. Of course one can only use compounds as photographic developingagents which have a suitable redox potential in the required pH region,i.e. which are capable of reducing silver halides to metallic silver.

The use of these substances for the purpose of the invention iscompletely different from their known use as photographic developers.According to the invention, these substances are used as reactants for acolor forming coupling reaction which requires the decomposition of theperoxide compound as oxidizing agent. The oxidative coupling reactionhas nothing whatever to do with the photographic devolopment of exposedsilver halide. Consequently, when these substances are used inaccordance with this invention, they are not required to satisfy anyconditions as regards their activity within certain, relatively narrowpH ranges.

However for catalytic dye formation the color forming agents must alsosatisfy certain requirements as regards their electrochemicalproperties. Thus, they should have an auodic redox potential which ismore negative at the pH values employed than the cathodic redoxpotential of the peroxide compound used, with the additional requirementthat the difference between these two redox potentials must not exceedthe value which corresponds to the activation energy required for the(non-catalytic) decomposition of the peroxy compound. However, theseactivation energies (and hence also the permissible potentialdilferences) are very high and furthermore it is possible by suitablechoice of various inorganic and/or organic peroxy compounds to cover analmost unlimited range of potentials. Hence even those compounds ofstructural formulae (I) and (II) which are not operative as photographicdevelopers are suitable for use as color forming agents for thecatalytic dye formation.

These substances which cannot be used as photographic developers yield,for example, brownish black to black dyes by catalytic dye formation onthe image silver by decomposition of the peroxy compound, in particularH 0 The substances for use according to the invention may also be usedin admixture with other reactants, e.g. pyrocatechol, resorcinol,orthoand para-phenylene diamines, diamine, N-allylandN,N-dialkyl-phenylenediamine. Further improvement in dye formation canthereby be obtained. These substances have been described e.g. inBritish Patent Specification No. 1,268,126 or US. Ser. No. 881, 610 nowUS. Pat. No. 3,674,490.

Production of the photographic images may be carried out in various waysby known methods. It is practically immaterial which peroxides activecatalysts distributed in accordance with the image are used for theimagewise activation of the peroxide compound. It is preferred to uselayers which upon exposure produce imagewise nuclei of noble metals ofthe Groups IB and/or VIII of The Periodic Table which in turncatalytically accelerate the decomposition of the peroxide compound.Photographic materials of this kind have been described in the aboveBritish Patent Specification.

Another suitable method of decomposing peroxide compounds imagewise hasbeen described in British Patent Application No. 46,694/70 and US.Patent Application Ser. No. 74,482. The said Patent Applications relateto a light-sensitive material which contains compounds which on exposureto light form catalase active and/or peroxidase active catalysts. Theseare complex compounds of metals of Groups VIB, VIIB or VIII of ThePeriodic Table of Elements.

A similar material has been described in British Patent Application57,633/70 and US. Patent Application Ser. No. 94,573 now US. Pat. No.3,684,511. According to the said Patent Applications, thelight-sensitive layer contains a compound which splits oft catalaseactive or peroxidase active iodine ions on exposure to light.

vAnother possible method has been described in British PatentApplication No. 51,141/70 and US. Patent Application Ser. No. 84,195 nowUS. Pat. No. 3,694,207. The material described there enables directpositive images to be produced. The light-sensitive layer containscatalase active and/or peroxidase active enzymes which are inactivatedon exposure to light. The material is then treated with hydrogenperoxide, decomposition then taking place only in the areas which havenot been struck by light.

Suitable peroxide compounds are e.g. inorganic peroxide compounds suchas perborates, percarbonates, persilicates, perphosphates orpersulfates. Organic peroxide compounds may also be used, e.g. benzoylperoxide. Hydrogen peroxide is particularly suitable owing to itsefiicient action and the ease with which it can be handled in the formof aqueous solutions. Especially useful are addition compounds v ofhydrogen peroxide with organic compounds, especially urea, acid amides,polyhydroxyl compounds or amines.

EXAMPLE 1 5 litres of an 8% aqueous gelatin solution are added to 1litre of a highly sensitive silver iodobromide gelatin emulsion (4.5mol-percent/Agl). The mixture is adjusted to pH 5.5. 200 g. of compound44 are then suspended in this mixture which is then cast on a support ofpoly- Bath I:

2 g. of 1-phenylpyrazolidone-3 25 g. of hydroquinone 100 g. of anhydrousNa SO 1 g. of polyethylene oxide wax made up to 1 litre with H adjustedto pH 11.5 with NaOH.

After brief washing, the layer is immersed for 10 seconds in a mixtureof the following composition at 35 C.:

Bath II:

700 cc. of 30% aqueous H 0 300 cc. of isopropanol 5 cc. of acetone.

In this bath, a black dye image (negative of the exposure original) isproduced catalytically on the image silver with the aid of the peroxideintroduced into the layer.

The layer is finally stabilized and fixed by introducing it for secondsinto a solution of the following composition at 35 C.:

Bath III:

100 g. of Na S O 2 g. of KSCN 20 g. Of A12(SO4)3 in 1 litre of H20adjusted pH 12 with NaOH.

This bath HI stabilizes the dye image to such an extent that subsequentwashing is not absolutely necessary. A brief final washing (e.g. 10seconds) is recommended only if the images are to be stored for a longtime (e.g. longer than 2 months).

The color density of the dye image can be increased by briefly heatingthe layer between bath H and bath III (e.g. by infra-red radiation for10 seconds at about 80 C.).

EXAMPLE 2 Preparation of the light-sensitive material:

20 g. of green ammonium ferricitrate are dissolved in 80 cc. of water 6g. of ammonium ferrioxalate are dissolved in 60 cc. of

water 5 g. of K Fe(CN) are dissolved in 50 cc. of water 1 g. of citricacid is dissolved in 10 cc. of water 12 g. of gelatin are dissolved in200 cc. of water.

The above solutions are mixed together in red darkroom light and themixture is cast on a support of cellulose triacetate. The thickness ofthe dried layer is about 10 to 20,. The layer is hardened in the usualmanner, by addition of a 2 ml. of a 30% aqueous solution of formalin ormucochloric acid.

Processing: The dried layer is exposed imagewise behind a grey step in aconventional sensitometer (100 watt lamp, exposure time 10 seconds). Itis then exposed to a water vapour atmosphere at about 80 C. for about 10to 20 seconds and then hardened for 30 seconds by spraying water on it.

10 The layer is then introduced into a bath (I) ofthe followingcomposition for 30 seconds:

Bath I:

500 cc. of 30% H 0 500 cc. of a saturated aqueous solution ofl-phenylethanol 25 g. of the sodium salt of benzilic acid.

It is then treated for 30 seconds with Bath H:

16 g. (N,N-diethyl)p-phenylenediaminsulfate 20 g. of compound 1 9 g. ofsodium sulfite made up to 1 litre with H 0 adjusted to pH 9.5 with K COIt is then stabilized by immersing it for 30 seconds into a solution ofBath HI:

25 g. of ZnSO -7H O in 1 litre of H 0 with citric acid/citrate bufferadjusted to pH 5.

A black negative image of the original is obtained.

EXAMPLE 3 A transparent support of cellulose triacetate is coated with asolution containing 6 ml. of a 10% aqueous solution of polyvinyl alcoholand 2 g. of TiO: reduced to a particle size of 0.3 to 0.4 pm. and 0.1mg. of erythrosine as spectral sensitizer in 400 cc. of water. The layeris then dried.

The dried layer is exposed imagewise and then treated for 30 seconds inthe following bath at 20 C.:

Bath I: 2% aqueous NaPd(C O solution.

After brief washing, the layer is introduced for 30 seconds into asolution of the following composition at 20 0.:

Bath H:

500 CC. 0f 30% H203 450 cc. of cyclohexanol 40 cc. of cyclohexanone and10 cc. of ethyl methyl glycol.

The layer is then introduced for 30 seconds into a bath of the followingcomposition at 20 C. to effect catalytic dye formation:

Bath 1H:

10 g. of compound 45 50 g. of pyrocatechol 9 g. of anhydrous Na SO madeup to 1 litre with H O adjusted to pH 8 with Na CO The layer is finallystabilized by introducing it for 30 seconds into the following solutionat 20 C.:

12 g. of lead acetate in 1 liter of H 0 (adjusted to pH 6 withacetate/acetic acid buffer). A deep black image of the original isobtained.

We claim:

1. In a process for the production of photographic images by imagewiseexposure of a lightsensitive layer wherein noble metal nuclei areproducible, producing in 'the layer in imagewise distribution nuclei ofnoble metals of Groups Ib and VIII of The Periodic Table of Elementscapable of catalytically decomposing peroxy compounds,

treating the layer which contains the imagewise distributed noble metalnuclei in the presence of a color forming compound which on oxidationyields a dye, with a peroxy compound thereby catalytically decomposingsaid peroxy compound on the noble metal nuclei'and oxidizing said colorforming compound to yield a dye image, wherein the improvement comprisesthe color forming compound is an organic compound having an anodic redoxpotential more negative than the cathodic redox potential of the 11 12peroxy compound and containing a CN single or double 2. The process ofclaim 1, wherein the color forming bond according to the followingformulae: component is reacted in admixture with other aromatic amines,phenols and/or aminophenols. R: Rifi R1 mil-1 km R -J:= 5 ReferencesCited (I) n UNITED STATES PATENTS wherein 3,674,490 7/1972 Metejec 96 48PD 3 503 744 3/1970 Itano 96-48 R R =aryl substituted with hydroxyland/0r ammo groups R2=hydmgen, alkyl or and 10 3,697,275 10/1972Hayakawa et al 9648 R 11: and}; have the same meimng as R RONALD H.SMITH, Primary Examiner as esame meamn as ()1? alternatively g 1 I. L.GOODROW, Assistant Examiner R and R and/or R and R may also denote thering members required to complete a heterocyclic saturated 15 9688 90 RUs or unsaturated S-membered or 6-membered ring.

